a crystal has a regularly repeating arrangement of atoms
Normally, oxygen from the blood cells supply your muscles with the energy it needs to carry out certain actions. However, when there isn't enough oxygen to support the muscles, it produces lactic acid, or fermentation, to make up for the oxygen. (That's why you get that burn-y feeling whenever you exercise!)
In early summer wasps, like bees, pollinate plants and flowers as they feed on nectar. If we were to eradicate all wasps, it would cause more problems than it would solve. So, wasps do serve a purpose, and despite being a problem at certain times of the year, they are a beneficial insect.
Question 2
D) Carbohydrates
Positive: You get to see different animals, see all kinds of habitats, learn new facts about all the animals and see them maybe in action!
Negative: They might be sleeping, In a cage or fence so they can't get out, restricted.